In many locations storm water collection systems for returning the water to storm sewers and the like are not available; however, the relatively large volume and rate of flow of such storm water must nevertheless be appropriately collected and channeled for return to the soil. In its most rudimentary sense, an injection well may simply be a hole in the ground filled with suitable rock backfill into which the water to be disposed is directed. Such simple wells, and a variety of improvements and modifications there of, are appropriate for application to domestic waste water or other systems having similar water flow rates (generally approximately 1,500 gallons per day). In contrast to such modest flow rates, storm water collection systems must accommodate intermittent but periodically recurring flow rates of significantly higher magnitude. For example, flow rates of one to two cubic feet per second (over 1 million gallons per day) must be accommodated by single storm water injection wells of the type described herein.
Since the water rates are extremely high prior art structures have concentrated techniques for accommodating such large flow rates and disposing of the storm water. The prior art has also addressed the difficulty of system clogging or clogging of a backfill medium by silt washed into the system with the storm water. To separate such silt from the water it was typical to employ a settling chamber which would hopefully permit an appropriate quantity of the storm water to stand a sufficient length of time to permit silt particles to settle out of the water prior to its being discharged to the surrounding soil. Similarly, prior art techniques have used filters in an attempt to block the passage of such silt into the soil.
Notwithstanding prior art endeavors, the transmission of silt, debris and trash can create severe problems over a period of time with such prior art storm water injection wells. Concentrated sources of unwanted materials such as landscape surface silt and debris (mulch, peat moss, grass, sediment from erosion) can severely decrease injection well efficiency. Another significant difficulty encountered with such injection wells is the fact that the storm water frequently is being collected from surfaces that are paved or are covered with other composition materials. Further, the areas being drained usually are associated with vehicles such as roads and parking lots. Accordingly, pavement oils and other impurities are washed by the storm water into the injection well. The recharging of ground water with such storm water can very easily become a health hazard as a result of oils or other chemicals that eventually find their way through the soil to subterranean aquifer. Such pavement oils also seriously adversely affect the performance of the injection well by clogging the surrounding soil and reducing the capacity of the well and its ability to accommodate large flow rates.